Thursday, October 13, 2005

Dr. Vector reviews Serenity

I saw Serenity for the second time last weekend, and I had a good chance to really appreciate just how damn well-written it is. Every conversation does some work, advancing the characterization or the plot or usually both at once. Most of them are such good back-and-forths that they remind you of the best writing by Leigh Brackett (The Big Sleep, The Empire Strikes Back) and Orson Scott Card (the later Shadow novels), where you can scarcely believe that this amazing exchange could come out of the head of a single, sane human being. But the movie doesn't feel like a philosophical exercise or a clockwork gadget or a sheer creative stunt, as tightly-written movies often do (I'm thinking here of The Matrix, The Maltese Falcon, and Adaptation, respectively). It feels like watching your favorite team play a close championship game against their nemesis. (I would have said it feels like a roller-coaster, but that has been so overused that it actually doesn't mean anything any more; it's lost its ability to provoke any response other than boredom or contempt.) There are no down times, no boring parts, never a moment where what's going on on screen isn't important, even urgent (keep in mind that I'm still talking about the conversations here--I haven't gotten to the action yet).

Oh, yeah, the action. Another thing that has become way too cliche in the last few years is to say of a movie that "every fight tells a story". That was splattered all over the promotional material for the Star Wars prequels, but there and everywhere else the phrase is just empty verbiage. As entertaining as it is to watch, when Obi-Wan and Jango Fett duke it out, you don't learn anything about them as people. They might as well be wind-up toys pointed at each other and released. The only question is, which one is going to get to pull the trump move. Don't get me wrong, fights like that can still be thrilling, but they're good for the gut, not the head, and sometimes you find your brain thinking treacherous thoughts, like "this isn't as engaging as it's supposed to be".

Contrast that to the fights in Serenity, particularly between Mal and the operative, where in the course of the fights you learn something about the political leanings, personal philosophies, histories, motivations, and limits of both combatants (in addition to watching them open up big cans of ball-stomp). Real, important information is conveyed. The fights really do tell a story--or, more honestly, the ongoing story continues to be told through the fight, instead of being interrupted for a set-piece battle. That was a real problem with the Star Wars prequels. They were long series of set-piece battles, with precious little space in between to, you know, tell a story. Develop the characters. Make them more than mouthpieces for
dumb, transparently expository dialogue.

But it would be misleading to say of Serenity that every fight tells a story. It's more accurate to say that every _thing_ tells a story. The whole alchemical stew of scenery, shot, camera movement (did I mention how well-directed the movie is?), dialogue, character, plot, action, fx--it's all one big, intricate machine, like some Rennaissance mechanism of nested, rotating rings. The machine's function is to draw you into another universe, give you something to invest in, and then return your investment many times over.

What more do you want? Go see the damn movie.

Wednesday, October 12, 2005

Big Explosions

I originally put this together in July, 2004. All the links are still good as of this posting.


I just finished reading John MacPhee's The Curve of Binding Energy, which is about nuclear weapon designer and Orion inventor Ted Taylor. I got curious about the largest conventional explosions and the smallest nuclear explosions. I present you with the results of my research.


Big explosions are measured in terms of tons, kilotons (kt), and megatons (Mt) of TNT equivalent. For comparison, the largest oil tankers approach a million tons in displacement. Imagine detonating an equivalent mass of TNT. That's a 1Mt explosion.

Some explosions of varying sizes, listed from smallest to largest:
- Oklahoma City bombing: ammonium nitrate fertlizer bomb, equivalent to 2.5-5 tons of TNT
- MOAB, the largest conventional weapon in the US arsenal: 18,000 lbs of high explosive, or 0.009kt. The "Grand Slam" bomb used by the UK in WWII was of approximately equal yield.
- Hiroshima bomb "Little Boy": 13kt (1/77 of a Mt)
- Nagasaki bomb "Fat Man": 20kt
- Castle Bravo, largest US nuke test: 15Mt (750 x Fat Man)
- Mt. Saint Helens inital explosion: 24Mt (7 by blast, the rest as heat)
- Tunguska blast: 40Mt
- Largest Soviet nuke test, and largest human-generated explosion of all time: 57Mt (2850 x Fat Man)
- Krakatoa: 100-200Mt, depending on who you ask
- The collision of the largest fragment of comet Shoemaker-Levy 9 (fragment G, two miles in diameter) with Jupiter is estimated at about 6 million Mt.


"The largest single conventional explosive detonation was for the demolition of the German fortifications at Helgoland on April 18, 1947. A charge of 4061 tonnes (8,952,961 lb) was detonated by Commissioned Gunner E.C. Jellis of the Royal Navy demolition team headed by Lt. F.T. Woosnam aboard HMS Lasso lying 14.5 km. (nine miles) out to sea."

In 1944, an ammo dump in the British Midlands blew. About 4000 tons of ammo went off. I assume that the resulting explosion was probably well short of 4kt because the total weight of munitions included the metal jackets, projectiles and bullets, and some smoke rounds.

In 1947, two liberty ships full of ammonium nitrate fertilizer blew up in Texas City on the Houston ship channel. One ship held 2300 tons of fertilizer, and the other 1000 tons. The 2300-ton lot blew first, but according to reports the subsequent detonation of the 1000-ton lot was more violent.

"The largest conventional explosion test conducted in the US invovled 4.36x10^9 g of explosive and produced a crater 88.4 m in diameter." That's 4360 metric tons of whammy kablammy, or 4807 US (short) tons, or 4430 avoirdupois (long) tons, or 9,592,000 pounds.


If that last source is right, then Guinness is wrong. The folks at Guinness may be aware of the 4.36kt test shot but not be able to authenticate it for military security reasons. In any case, at least two deliberate conventional explosions have been in the 4kt range--a third of Hiroshima, a quarter of Nagasaki--which is a-freakin-mazing.


Here's an eye-opener for you. The smallest nuclear weapon ever deployed by the US was the Davy Crockett unguided rocket, which had a maximum range (for the 120 mm version) of 1.24 _miles_ and a predicted yield of only 10 tons (comparable to Grand Slam or MOAB, in other words). It could be fired from a jeep. Between 1956 and 1963, 2100 were built. Actual tests of the W54 warhead at the Nevada Test Site in 1962 yielded 18 and 22 tons.

This site lists names, dates, locations, and yields of every US nuclear weapon test, and has pictures of many of the test shots. It is worth reading the details on the Pascal A and Pascal B shots from the Plumbob series. Both were safety tests with zero predicted yield. They actually yielded 55 and 300 tons, respectively, much to the surprise of the assembled observers. According to the site, one of the test shots that "fizzled" (Lassen, also from Plumbob series) had a yield of only 0.5 tons. However, the smallest nuclear explosion was the Able shot from Operation Buster, which had a yield of less than one pound. From the site: "The device achieved supercriticality and produced detectable nuclear output, but the energy produced was negligible compared to the high explosive used."


Fizzles aside, it is clearly possible to design nuclear weapons with predictable yields in the 10-20 ton range, and has been since the 1950s. How small can a nuke get? At some point, the energy released by the high explosive required to achieve supercriticality will be greater than the energy released by nuclear fission. I'm not sure where that point is, and I'm sure it's classified.


If we discount the Buster Able and Plumbob Lassen fizzles, the smallest 'real' nuclear explosion is the W54 test that yielded 18 tons. That's .004 times the size of the LCE listed above. So the LCE and SNE overlap by a factor of about 250.


The Halifax explosion, possibly the largest ever when it happened in 1917, but only about 200 tons of whammy kablammy.

Meteor Crater in Arizona, estimated at 20 Mt.

More on MOAB and other large conventional bombs. Incidentally, the 15,000 lb "daisy-cutters" used by the US to create instant helicopter landing sites in Vietnam and Afghanistan used an ammonium nitrate slurry. Fertilizer, in other words.

Low-yield earth-penetrating nuclear weapons.

Indian and Pakistani nukes may have fizzled.


A page with way too much stuff on war in space, and some pretty cool covers from old pulps and comics:


Dr. Vector

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